This invention relates to multi-stage fuel pumps such as are used in marine engine systems, and more particularly, to a two-stage fuel pump which is used in a stand alone configuration in such systems.
In co-pending, co-assigned U.S. patent application Ser. No. 551,586/09 filed Apr. 18, 2000, there is described a two-stage marine fuel pump used in an integrated fuel system. As described therein, the pump includes first and second pumping elements commonly mounted on a motor driven shaft. Fuel drawn into an inlet of the pump is pumped through the first element (comprising a first pump stage). Fuel expelled from the first stage is pumped into a reservoir from which it is drawn into an inlet of the second pump stage. Outlet fuel from the second stage is pumped to a fuel rail for delivery to a marine engine. All of the pump components are installed in a common housing and the pump has only a single fuel inlet and a single fuel outlet.
It has now been found that the two-stage pump is also useful in a variety of other fuel system configurations. In these applications, it is now advantageous to separate the first stage from the second stage so that even though the common mounting construction of components in the pump is the same as described in the co-pending application, routing of fuel to and from the pump stages allows greater flexibility in use of the pump.